CEDAR: Exploration of Trends in Thermospheric+Exospheric Hydrogen Using H-Alpha Emission Intensities and Hydrogen Column Abundances Retrieved from the Wisconsin Long Term Record

CEDAR：利用从威斯康星州长期记录中检索到的 H-Alpha 发射强度和氢柱丰度探索热层外层氢的趋势

• 批准号: 0334611
• 负责人: Susan Nossal
• 金额: --
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-01-15 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0334611&HistoricalAwards=false
• 关键词: CEDAR; Exploration; Trends; Thermospheric+Exospheric; Hydrogen

Upward fluxes of hydrogen containing molecules such as methane, water vapor, and molecular hydrogen are the primary source of hydrogen-containing chemical species in the middle and upper atmosphere. Understanding the sensitivity of the thermosphere and exosphere to hydrogenous species distributions below, to sources of natural variability, and to possible long-term climatic changes are central questions for geocoronal research. Observations of thermospheric and exospheric hydrogen-alpha column emissions by the Wisconsin H-alpha Mapper Fabry-Perot (WHAM) over the 1997-2001 rise in the solar cycle are the first Wisconsin-based observations to show a statistically significant solar cyclical variation in the geocoronal H-alpha emission, with higher emissions during solar maximum periods. These observations are scheduled to continue over the decline in the solar cycle, through at least 2005. The WHAM observations corroborate suggestions of such a trend seen in past mid latitude Wisconsin-based H observations. Collectively, this long term, consistently calibrated data record now spans two solar cycles. The research focuses on: analysis of and examination of trends in Fabry-Perot observations of thermospheric and exospheric H intensities; forward modeling retrieval of the thermospheric and exospheric hydrogen column abundance using a global resonance radiative transport code; and comparison of hydrogen column densities retrieved from H observations with those generated using output from a global mean model and the Thermosphere-Ionosphere-Mesosphere Electrodynamics General Circulation Model (TIME-GCM) as input to the radiative transfer code. A primary component to understanding the earth's climate and climate change due to human activities is knowledge of natural variability in the atmosphere. This study contributes to this effort by investigating the influence on upper atmospheric hydrogen of changes in the sun's ultraviolet output over the solar cycle. Upper atmospheric hydrogen is a byproduct of hydrogenous species chemistry in the middle atmosphere, involving molecules such as methane and water vapor, two primary atmospheric greenhouse gases. It is anticipated that characterization of upper atmospheric hydrogen, together with observational diagnostics lower in the atmosphere, will contribute to studies of vertical patterns in hydrogen containing species and their influence upon one another. The WHAM data add to a long-term body of hydrogen emission data now spanning a 20 year period. Their high precision and signal-to-noise facilitate comparisons with past and future data sets. This work will continue current educational and public outreach efforts focused on enhancing scientific literacy concerning climate change and other atmospheric topics, and on promoting diversity in the study of science.

含有分子（例如甲烷，水蒸气和分子氢）的氢的向上通量是中部和上层大气中含有氢化学物质的主要来源。了解下面的热层和外层对氢源分布的敏感性，对自然变异性的来源以及可能的长期气候变化的敏感性是地球研究的核心问题。威斯康星州H-Alpha映射器Fabry-Perot（WHAM）在1997 - 2001年度太阳周期中对热层和外部氢 - α柱排放的观察是第一个基于威斯康星州的观察值，它显示出统计上具有统计上显着的在地理位量H-Alpha的统计上具有统计上显着的Solar周期性变化，并在较高的al-Alpha中溶于较高的时期。这些观察结果计划在太阳周期的下降，至少至2005年。WHAM观察证实了对过去威斯康星州中期HISTITUS H的H观察结果的这种趋势的建议。总体而言，这一长期校准的数据记录现在跨越了两个太阳周期。该研究重点是：对热层和外层H强度的Fabry-Perot观测趋势的分析和检查；使用全球谐振辐射传输代码，对热层和外层氢柱的丰度进行前向建模。并比较从H观测值中获取的氢柱密度与使用全球平均模型和热层 - 层间层电动力学通用循环模型（Time-GCM）作为辐射传输代码输入的输出产生的氢柱密度。了解人类活动引起的地球气候和气候变化的主要组成部分是对大气中自然变异性的了解。这项研究通过研究太阳周期中太阳紫外线输出的变化的影响来促进这项工作。上大气中的氢是中间大气中氢化物质化学的副产品，涉及分子，例如甲烷和水蒸气，两种主要的大气温室气体。可以预见的是，大气上氢的表征以及大气中的观察性诊断将有助于研究含有物种的氢及其对彼此的影响的垂直模式。 WHAM数据增加了长期的氢排放数据，现在跨越了20年的时间。它们的高精度和信噪比有助于与过去和将来的数据集进行比较。这项工作将继续进行当前的教育和公共外展工作，致力于增强有关气候变化和其他大气主题的科学素养，以及促进科学研究的多样性。